Abstract

Coupled donor states induced by Sn doping into InP and their behaviors were studied by employing photoluminescence(PL) measurements and first-principles calculations.InP: Sn crystals were grown in the [100] orientation by a modified liquid-encapsulated vertical Bridgman technique. The PL data show a donor-acceptor recombination line and its phonon replica at 898 nm and 926 nm, respectively, and another recombination line around 800 nm, which uniquely appears at the top in high Sn concentration. The first-principles calculations for the InP:Sn system support these results by observing two separate donor levels below and above the bottom of the conduction band, which are responsible for the recombination lines. They deviate from the bottom of the conduction band with the increase of Sn concentration. A peak at 879 nm from the band-to-band transition could only be visible at room temperature. The PL mapping of this line shows the increase of Sn concentrations with the crystal growth, which helps to reduce the dislocation density and increase the lifetime of excess carriers.

Received 26 April 2007Accepted 24 September 2007Published online 30 November 2007

Acknowledgments:

The authors are grateful to Professor Zhanguo Wang, Dr. Yonghai Chen, and Heping Lu of the Laboratory of Semiconductor Materials Sciences of the Institute for Semiconductors of the Chinese Academy of Sciences for making these experiments possible. We would like to thank Professor Stewart Edward Barnes of the Department of Physics of Miami State University for his helpful discussion. This work was partly supported by the “863” Program (2006AA03A110), the National Nature Science Foundation (Grant No. 60776066), and grants from the Ministry of Education, Fujian Province, and Xiamen of China.